1. Field of the Invention
The present invention relates to a rodless cylinder which functions, for example, as a transport means for a workpiece.
2. Description of the Related Art
In recent years, various rodless cylinders have adopted as means for transporting workpieces in factories and the like. Those known as the conventional rodless cylinder include a mechanism in which a bearing is provided between a guiding component and a load-transmitting component. The guiding component and the load-transmitting component are formed to be mutually rotatable about the bearing axis, and they are provided to be mutually movable by predetermined amounts in the axial direction of the bearing. Thus, the load, which is exerted on the guiding component or the load-transmitting component, is absorbed (see Japanese Laid-Open Patent Publication No. 60-234106).
Those known as the conventional rodless cylinder include another mechanism in which an engaging recess is formed on a lower surface of a slider. An engaging projection for making engagement with the engaging recess is provided on an upper surface of a yoke which is formed integrally with a piston. The load in the horizontal and vertical directions is absorbed by the aid of a gap formed between the engaging projection and the engaging recess. Planar torsion is absorbed by the aid of an arc surface formed on the engaging projection (see Japanese Patent Publication No. 7-1041).
However, the technical concept disclosed in Japanese Laid-Open Patent Publication No. 60-234106 involves the following inconvenience. That is, it is impossible to absorb the load exerted in the direction approximately parallel to the axis of a cylindrical member which functions as a cylinder body and in the direction perpendicular to the axis. Further, it is impossible to absorb the load exerted in the rotational direction about the axis of the cylindrical member.
On the other hand, the technical concept disclosed in Japanese Patent Publication No. 7-1041 involves the following inconvenience, because the arc surface formed on the engaging projection and the plane of an abutment component are provided so that they make line-to-line contact. That is, the arc surface is deformed by the load exerted on the engaging projection, resulting in deterioration of durability.